It is the position of The American Dietetic Association that functional foods, including whole foods and fortified, enriched, or enhanced foods, have a potentially beneficial effect on health when consumed as part of a varied diet on a regular basis, at effective levels. The Association supports research to further define the health benefits and risks of individual functional foods and their physiologically active components. Dietetics professionals will continue to work with the food industry, government, the scientific community, and the media to ensure that the public has accurate information regarding this emerging area of food and nutrition science. Knowledge of the role of physiologically active food components, both from phytochemicals and zoochemicals, has changed the role of diet in health. Functional foods have evolved as food and nutrition science has advanced beyond the treatment of deficiency syndromes to reduction of disease risk. This position reviews the definition of functional foods, their regulation, and the scientific evidence supporting this emerging area of food and nutrition. Foods can no longer be evaluated only in terms of macronurtrient and micronutrient intake. Analyzing the content, of other physiologically active components will be necessary. The availability of health-promoting functional foods in the US diet has the potential to help ensure a healthier population. However, each functional food should be evaluated on the basis of scientific evidence to ensure appropriate integration into a varied diet.